Plyometrics - Plyometrics As Simple Jumping (with Little Regard For Time of Execution)

Plyometrics As Simple Jumping (with Little Regard For Time of Execution)

The most common type of plyometrics used in the United States is simple and relatively easy jump exercises executed with little regard to execution time. These jumps are effective for athletes who execute skills in their sport that do not require explosive type muscular contractions. An example is long-distance running, in which the runners execute repeat actions of 20 to 30 consecutive jumps and other cyclic type activities such as leaping for multiple repetitions.

Such plyometric jumps are also used as a warm-up to doing explosive plyometric jumps and for initial preparation of the muscles prior to undertaking exercises such as depth jumps. In essence, they are effective in the early stages of learning how to do plyometric exercises and for preparing the muscles for explosive or quick jumps. These jumps are similar to those done by youngsters in the playground or in neighborhood games and as such, do not require additional preparation. Athletes, regardless of their level of expertise, can undertake such jumps in the initial stages of training.

When athletes who have been doing plyometrics without regard to time of execution first attempt to execute explosive plyometrics, they often fail because the time of execution is too long. This occurs quite often in the depth jump. The athlete usually sinks (drops) too low which takes too long to make the transition from the eccentric to the concentric contraction. As a result, the exercise becomes a jump strength exercise and not a true plyometric one.

Jump technique remains the same regardless of whether it is a true plyometric exercise or a jump exercise. There is flexion in the hips, knees and ankles on landing and extension in the joints on the upward return. The sequence and overlapping in the sequence is basically the same beginning with the hip extension followed by knee extension and ending with ankle plantar flexion. The major differences in execution are in the depth of the landing and in the time of executing the switch from the eccentric to the concentric contraction.

Studies have been conducted testing ten various plyometric exercises on overall performance during jumping examined by EMG, power, and ground reaction force (GRF). Of the 10 tested, the single leg cone hops, box jumps, tuck jumps, and two legged vertical jumps produced the highest EMG values eluding to greater motor recruitment. Power was examined by: dumb bell jumps, depth jumps, countermovement jumps, squat jumps, and tuck jumps which all produced the higher power scale readings. In terms of athletic performance and training, the plyometric movements that utilize total body vibration produced an overall in crease in performance output. In one recent study examining two groups using the same plyometric protocol in combination with weight training, one using high loads and the other utilizing small loads, similar decreases in power were found. This shows that the plyometric exercises themselves had a greater effect in the decrease in power output rather than the type of weight training.